Hypoid gear forming process

ABSTRACT

A hypoid bevel gear roll forming process wherein either a bevel ring gear rough-cut workpiece or a bevel pinion gear rough-cut workpiece is finish-formed by a die whose teeth are identical in shape to a finished bevel pinion gear and ring gear, respectively, with the die, in either instance, being the rotary powered unit and the ring gear, whether die or workpiece, being axially advanced to a finish mesh position with the pinion gear.

United States Patent [191 Fountain et a1.

[ HYPOID GEAR FORMlNG PROCESS [75] Inventors: Edgar A. Fountain, Charlotte; John C. Bachelder, Lansing; Keith D. Miller, Grand Ledge, all of Mich.

[731 Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: Aug. 31, 1972 [21] Appl. N0.: 285,550

[52] US. Cl. 29/l59.2 [51] Int. Cl B2ld 53/28 [58] Field of Search.., 72/84, 86, 80, 102, 107,

[56] References Cited UNITED STATES PATENTS 3,605,467 9/1971 White et al. 29/1592 Apr. 23, 1974 3,604,235 9/1971 Motz et al 29/1592 3,635,062 1/1972 Bregi et a1. 29/1592 3,579,803 5/1971 Lautenschlager 29/1592 Primary Examiner-Richard J. Herbst Attorney, Agent, or Firm-John P. Moran 5 7] ABSTRACT A hypoid bevel gear roll forming process wherein either a bevel ring gear rough-cut workpiece or a bevel pinion gear rough-cut workpiece is finish-formed by a die whose teeth are identical in shape to a finished bevel pinion gear and ring gear, respectively, with the die, in either instance, being the rotary powered unit and the ring gear, whether die or workpiece, being axially advanced to a finish mesh position with the pinion gear.

6 Claims, 5 Drawing Figures HYPOID GEAR FORMING PROCESS This invention related generally to gear forming processes and, more specifically, to a hypoid gear cold roll forming process.

At present, hypoid bevel gears suitable for operation in a vehicular rear axle differential arrangement are finished by gear cutting machines requiring relatively long machining times, thus generally necessitating a large number of such machines.

Accordingly, an object of the invention is to provide a cold roll forming process wherein either the rear axle differential bevel ring gear or bevel pinion gear is finished thereby.

Another object is to provide a gear roll forming process wherein the rear axle differential bevel ring gear is formed by a die whose teeth are similar in shape to a conventional hypoid bevel pinion gear, while the bevel pinion gear is formed by a die whose teeth are similar in shape to a conventional hypoid bevel ring gear.

A further object is to provide a hypoid bevel gear forming process wherein either the rough-cut bevel ring gear or the rough-cut bevel pinion gear is formed by a respective pinion gear-shaped or ring gear-shaped die, with the die, in either instance, being rotatably powered, while the ring gear, whether die or workpiece, is axially advanced until the gear has assumed a final position with respect to the pinion comparable to the relative positions of conventional hypoid bevel gears as assembled in the rear axle differential on an automobile, at which point the workpiece will have assumed a finish dimension and thus be ready to be hardened preparatory to final assembly.

These and other objects and advantages of the invention will be apparent when reference is made to the following description and accompanying drawings, wherein:

FIG. 1 is a perspective view of a machine tool which may incorporate the inventive method;

FIG. 2 is an enlarged fragmentary cross-sectional view ofa bevel ring gear workpiece and a bevel gear die in relative positions suitable for the inventive method;

FIG. 3 is an end view taken from the left of FIG. 2 illustrating the hypoid-type axial relationship between the workpiece and the die of FIG. 2;

FIG. 4 is an enlarged fragmentary cross-sectional view of a bevel pinion gear workpiece and a bevel ring gear die in relative positions suitable for the inventive method; and

FIG. 5 is an end view taken from the left of FIG. 4 illustrating the hypoid-type axial relationship between the workpiece and the die of FIG. 4.

Referring now to the drawings in greater detail, FIG. 1 illustrates a hypoid gear rolling machine with which the inventive method may be practiced. The machine 10 includes a base 12, sides 14 and 16, and a top 18. A vertical spindle assembly 20 is mounted in the base 12 intermediate the sides 14 and 16, and may be rotatably and/or reciprocally actuated therein by any suitable means (not shown), as will be explained. A bevel pinion gear 22, which may be a die or a workpiece, as will also be explained, is mounted on the top of the vertical spindle assembly 20. A horizontal spindle assembly 24 is mounted on top of the base 12, and may also be reciprocally and/or rotatably actuated thereon by any suitable means (not shown). A bevel ring gear 26, which also may be a. workpiece or a die, is mounted on the front of the horizontal spindle assembly 24.

A stock divider assembly 28 may be suspended from the top 18 just above the ring gear 26. The stock divider assembly 28 includes a rack member 30 slidably mounted in a fixed guide member 32. A handle 34 is mounted on the front of the rack member 30 to facilitate vertical manual movement of the rack member 30 in the guide member 32. A ball-end pointer 36 is secured to the bottom end of the rack member 30 for insertion between adjacent teeth 38 of the bevel ring gear 26 to initially properly position the ring gear 26 prior to the engagement of the teeth 38 of the ring gear 26 with the teeth 40 of the bevel pinion gear 22.

If a stock divider assembly 28 is included, a shot pin 42 coordinated therewith is required, slidably mounted on the top surface of the vertical spindle assembly 20, for insertion between adjacent teeth 40 of the bevel pinion gear 22, thus aligning the teeth 40 for the engagement therewith by the teeth 38 of the bevel ring gear 26.

In general, it is preferred that in every instance the die be mounted on the rotatably powered spindle unit and that the spindle unit on which the ring gear member is mounted, whether the latter be the die or the workpiece, be the axiallymovable unit, thereby avoiding the necessity of a threading or screwing action, as

would be required if the pinion gear member were moved axially into engagement with the ring gear memher.

A suitable bevel ring gear roll forming arrangement is illustrated in FIGS. 2 and 3. The workpiece 26, in this case a rough cut bevel ring gear, is held on the front of the horizontal spindle assembly 24 during the rolling cycle by a conventional chuck assembly 24 during the rolling cycle by a conventional chuck assembly 44. The die 22 is, in this case, formed in the shape of a finished bevel pinion gear, but having an overall length somewhat greater than that of a finished; pinion gear in order to extend past the inner and outer edges of the ring gear 26 while in mesh therewith. The die 22 is retained in place on the top of the vertical spindle assembly 20 by a suitable jig or holding fixture 46.

It may be noted in FIG. 3 that the axial relationship between the bevel ring gear 26 and the bevel pinion gear die 22 is that of a conventional automotive hypoid gear rear axle differential arrangement, i.e., the axes A and B of the intermeshed driving and driven bevel gears 22 and 26, respectively, are at right angles to one another, but not in the same plane, resulting in some sliding action between the intermeshed teeth.

In the bevel ring gear forming operation, after alignment of the respective gears 22 and 26 by the shot pin 42 and the stock divider pointer 36, respectively, the horizontal spindle assembly 24, along with the roughcut ring gear 26, is manually advanced along the axis 3" toward and into mesh with the teeth 40 of the pinion gear die 22, the torque of the assembly 24 being predetermined so as to move the ring gear or workpiece 26 to within approximately 0050-0060 inch of the finished depth with respect to the die 22. The horizontal spindle assembly 24 thereupon is fed automatically through the final 0.050-0060 inch during approximately a 15-second roll forming cycle during which the die 22, which is the hardened member, is caused to do the driving by virtue of the vertical spindle assembly 20 being the rotatably powered unit. It is preferred that the workpiece not be used as the driving member.

At the conclusion of the l-second cycle, the now finished ring gear 26 is retracted by the horizontal spindle assembly 24, and removed from the chuck assembly 44, ready for hardening.

A suitable bevel pinion gear roll forming arrangement is illustrated in FIGS. 4 and 5. The workpiece 22, in this case, a rough-cut bevel pinion gear, is held on the front of the horizontal spindle assembly 24 during the rolling cycle by a collet assembly 48. The die 26 is, in this case, formed in the shape of a finished bevel pinion gear, but having an overall tooth 38 width somewhat greater than that of a finished ring gear in order to extend past the front and rear edges of the pinion gear 22 while in mesh therewith. The die 26 is retained in place on the top of the vertical spindle assembly by a suitable jig or holding fixture 50.

The same offset A and B axes arrangement as is shown in FIG. 3 is utilized in the FIG. 5 arrangement.

In the bevel pinion gear forming operation, after alignment of the respective gears 22 and 26 by the shot pin 42 and the pointer 36, respectively, the vertical spindle assembly 20, along with the rough-cut ring gear 26, is manually advanced along the axis A toward and into mesh with the teeth 40 of the pinion gear 22, the torque of the assembly 20 being predetermined so as to move the ring gear die 26 to within 0.0500.060 inch of the finished depth with respect to the pinion gear workpiece 22. The vertical spindle assembly 20 thereupon advances automatically through the final 0.0500.060 inch during approximately a l5-second roll forming cycle during which the die 26, which is the hardened member, is caused to do the driving by virtue of the vertical spindle assembly 20 also being the powered unit.

At the conclusion of the l5-second cycle, the now finished pinion gear 22 is removed from the collet assembly 48 after the vertical spindle assembly 20 is axially retracted therefrom. The gear 22 is now ready for hardening prior to final assembly with a finished ring gear 26.

It should be apparent that, if desired, the horizontal spindle assembly 24 could be the powered unit and either spindle assembly could be the advancing or fed unit, but, as indicated above, it is preferred but not essential that the ring gear member, whether die or workpiece, be mounted on the axially fed spindle unit.

It will also be apparent to those skilled in the art that the hypoid gear roll forming process taught by the invention provides an extremely rapid and substantially simplified hypoid gear finishing operation as compared to the time-consuming hypoid gear cutting methods currently utilized.

While but two embodiments of the invention have been shown and described, other modifications thereof are possible.

We claim:

1. A bevel gear cold roll forming process including the following steps:

a. mounting a bevel ring gear member on a first machine tool spindle assembly;

b. mounting a bevel pinion gear member on a second machine tool spindle assembly, said second machine tool spindle assembly having its axis at right angles to the axis of said first machine tool spindle assembly but not in the same plane therewith, one of said bevel ring gear and pinion gear members being a rough machined workpiece and the other being a finished machined and hardened die;

c. axially advancing said first spindle assembly so as to bring said bevel ring gear member into mesh with said bevel pinion gear member to within a predetermined distance apart from a finish mesh position;

d. rotating said spindle assembly bearing said die under power and thereby driving said workpiece while axially feeding said first spindle assembly bearing said bevel ring gear member through said predetermined distance to said finish mesh position; and

e. stopping said spindle assembly bearing said die, re-

tracting said first machine tool spindle assembly bearing said bevel ring gear member and removing the now finished workpiece.

2. The bevel gear cold roll forming process described in claim 1, and:

a. employing a stock divider assembly operatively connected to said first spindle assembly to align the teeth of said bevel ring gear member in a predetermined circumferential position;

b. employing a shot pin arrangement operatively connected to said second spindle assembly and coordinated with respect to said stock divider assembly to align the teeth of said bevel pinion gear member in a predetermined circumferential position for being engaged by said teeth of said bevel ring gear member upon said advancement of said first spindle assembly.

3. A bevel gear cold roll forming process including the following steps:

a. mounting a bevel ring gear member on a first machine tool spindle assembly adapted to being axially fed;

b. mounting a bevel pinion gear member on a second machine tool spindle assembly adapted to being rotatably powered; said second machine tool spindle assembly having its axis at right angles to the axis of said first machine tool spindle assembly but not in the same plane therewith, said bevel ring gear member being a rough machined workpiece and said bevel pinion gear member being a finish machined and hardened die;

0. axially advancing said first spindle assembly so as to bring said bevel ring gear member into mesh with said bevel pinion gear member to within a predetermined distance apart from a finish mesh position;

d. rotating said second spindle assembly bearing said bevel pinion gear die under power and thereby driving said bevel ring gear workpiece while axially feeding said first spindle assembly bearing said bevel ring gear workpiece through said predetermined distance to said finish mesh position with said bevel pinion gear die; and

e. stopping said second spindle assembly bearing said bevel pinion gear die, retracting said first machine tool spindle assembly bearing said bevel ring gear member and removing the now finished bevel ring gear member therefrom.

4. A bevel gear cold roll forming process including the following steps:

a. mounting a bevel pinion gear member on a first machine tool spindle assembly adapted to permit said pinion gear member to be freely rotatable thereon;

b. mounting a bevel ring gear member on a second machine tool spindle assembly, said second machine tool spindle assembly having its axis at right angles to the axis of said first machine tool spindle assembly but not in the same plane therewith, said bevel pinion gear member being a rough machined workpiece and said bevel ring gear member being a finish machined and hardened die;

0. axially advancing said second spindle assembly so as to bring said bevel ring gear member into mesh with said bevel pinion gear member to within a predetermined distance apart from a finish mesh positron;

d. rotating said second spindle assembly bearing said bevel ring gear die under power and thereby driving said bevel pinion gear workpiece while axially feeding said first spindle assembly bearing said bevel ring gear die through said predetermined distance to said finish mesh position with said bevel pinion gear workpiece; and

e. stopping said second spindle assembly bearing said bevel ring gear die, retracting said first machine tool spindle assembly bearing said bevel pinion gear member and removing the now finished bevel pinion gear member therefrom.

5. A bevel gear cold roll forming process including the following steps:

a. using a chucking device to mount a rough machined hypoid bevel ring gear-shaped workpiece on a first machine tool spindle assembly adapted to being axially fed;

b. using a holding fixture to mount a finished, hardened hypoid bevel pinion gear-shaped die on a second machine tool spindle assembly adapted to being rotatably powered, the axes of said first and second spindle assemblies being mounted in the same relative positions as the axes of a predetermined vehicular rear axle differential hypoid bevel gear arrangement;

c. actuating said first spindle assembly to advance said workpiece into mesh with said die to approximately within 0.060 inch of a finish mesh position;

d. actuating said second spindle assembly to rotate said die and thereby drive said workpiece while actuating said first spindle assembly to axially feed said workpiece through said 0.060-inch distance; and

e. stopping said second spindle assembly and said die, and retracting said first spindle assembly and removing the now finished hypoid bevel ring gear from said chucking device.

6. A bevel gear cold roll forming process including the following steps:

a. using a collet mechanism to mount a roughmachined hypoid bevel pinion gear-shaped workpiece on a first machine tool spindle assembly adapted to permit said workpiece to be freely rotated thereon;

b. using a holding fixture to mount a finished, hardened hypoid bevel ring gear-shaped die on a second machine tool spindle assembly adapted to being rotatably powered and axially fed, the axes of said first and second spindle assemblies being mounted in the same relative positions as the axes of a predetermined vehicular rear axle differential hypoid bevel gear arrangement;

c. actuating said second spindle assembly to advance said die into mesh with said workpiece to approximately within 0.060 inch of a finish mesh position;

d. actuating said second spindle assembly to rotate said die and thereby driving said workpiece while actuating said first spindle assembly to axially feed said die through said 0.060-inch distance; and

e. stopping said rotary actuation of said second spindle assembly, actuating said second spindle assembly to retract said die, and removing the now finished hypoid bevel pinion gear from said collet mechanism. 

1. A bevel gear cold roll forming process including the following steps: a. mounting a bevel ring gear member on a first machine tool spindle assembly; b. mounting a bevel pinion gear member on a second machine tool spindle assembly, said second machine tool spindle assembly having its axis at right angles to the axis of said first machine tool spindle assembly but not in the same plane therewith, one of said bevel ring gear and pinion gear members being a rough machined workpiece and the other being a finished machined and hardened die; c. axially advancing said first spindle assembly so as to bring said bevel ring gear member into mesh with said bevel pinion gear member to within a predetermined distance apart from a finish mesh position; d. rotating said spindle assembly bearing said die under power and thereby driving said workpiece while axially feeding said first spindle assembly bearing said bevel ring gear member through said predetermined distance to said finish mesh position; and e. stopping said spindle assembly bearing said die, retracting said first machine tool spindle assembly bearing said bevel ring gear member and removing the now finished workpiece.
 2. The bevel gear cold roll forming process described in clAim 1, and: a. employing a stock divider assembly operatively connected to said first spindle assembly to align the teeth of said bevel ring gear member in a predetermined circumferential position; b. employing a shot pin arrangement operatively connected to said second spindle assembly and coordinated with respect to said stock divider assembly to align the teeth of said bevel pinion gear member in a predetermined circumferential position for being engaged by said teeth of said bevel ring gear member upon said advancement of said first spindle assembly.
 3. A bevel gear cold roll forming process including the following steps: a. mounting a bevel ring gear member on a first machine tool spindle assembly adapted to being axially fed; b. mounting a bevel pinion gear member on a second machine tool spindle assembly adapted to being rotatably powered; said second machine tool spindle assembly having its axis at right angles to the axis of said first machine tool spindle assembly but not in the same plane therewith, said bevel ring gear member being a rough machined workpiece and said bevel pinion gear member being a finish machined and hardened die; c. axially advancing said first spindle assembly so as to bring said bevel ring gear member into mesh with said bevel pinion gear member to within a predetermined distance apart from a finish mesh position; d. rotating said second spindle assembly bearing said bevel pinion gear die under power and thereby driving said bevel ring gear workpiece while axially feeding said first spindle assembly bearing said bevel ring gear workpiece through said predetermined distance to said finish mesh position with said bevel pinion gear die; and e. stopping said second spindle assembly bearing said bevel pinion gear die, retracting said first machine tool spindle assembly bearing said bevel ring gear member and removing the now finished bevel ring gear member therefrom.
 4. A bevel gear cold roll forming process including the following steps: a. mounting a bevel pinion gear member on a first machine tool spindle assembly adapted to permit said pinion gear member to be freely rotatable thereon; b. mounting a bevel ring gear member on a second machine tool spindle assembly, said second machine tool spindle assembly having its axis at right angles to the axis of said first machine tool spindle assembly but not in the same plane therewith, said bevel pinion gear member being a rough machined workpiece and said bevel ring gear member being a finish machined and hardened die; c. axially advancing said second spindle assembly so as to bring said bevel ring gear member into mesh with said bevel pinion gear member to within a predetermined distance apart from a finish mesh position; d. rotating said second spindle assembly bearing said bevel ring gear die under power and thereby driving said bevel pinion gear workpiece while axially feeding said first spindle assembly bearing said bevel ring gear die through said predetermined distance to said finish mesh position with said bevel pinion gear workpiece; and e. stopping said second spindle assembly bearing said bevel ring gear die, retracting said first machine tool spindle assembly bearing said bevel pinion gear member and removing the now finished bevel pinion gear member therefrom.
 5. A bevel gear cold roll forming process including the following steps: a. using a chucking device to mount a rough machined hypoid bevel ring gear-shaped workpiece on a first machine tool spindle assembly adapted to being axially fed; b. using a holding fixture to mount a finished, hardened hypoid bevel pinion gear-shaped die on a second machine tool spindle assembly adapted to being rotatably powered, the axes of said first and second spindle assemblies being mounted in the same relative positions as the axes of a predetermined vehicular rear axle differential hypoid bevel gear arrangement; c. actuating said first spindle assembly to advanCe said workpiece into mesh with said die to approximately within 0.060 inch of a finish mesh position; d. actuating said second spindle assembly to rotate said die and thereby drive said workpiece while actuating said first spindle assembly to axially feed said workpiece through said 0.060-inch distance; and e. stopping said second spindle assembly and said die, and retracting said first spindle assembly and removing the now finished hypoid bevel ring gear from said chucking device.
 6. A bevel gear cold roll forming process including the following steps: a. using a collet mechanism to mount a rough-machined hypoid bevel pinion gear-shaped workpiece on a first machine tool spindle assembly adapted to permit said workpiece to be freely rotated thereon; b. using a holding fixture to mount a finished, hardened hypoid bevel ring gear-shaped die on a second machine tool spindle assembly adapted to being rotatably powered and axially fed, the axes of said first and second spindle assemblies being mounted in the same relative positions as the axes of a predetermined vehicular rear axle differential hypoid bevel gear arrangement; c. actuating said second spindle assembly to advance said die into mesh with said workpiece to approximately within 0.060 inch of a finish mesh position; d. actuating said second spindle assembly to rotate said die and thereby driving said workpiece while actuating said first spindle assembly to axially feed said die through said 0.060-inch distance; and e. stopping said rotary actuation of said second spindle assembly, actuating said second spindle assembly to retract said die, and removing the now finished hypoid bevel pinion gear from said collet mechanism. 